Textile grafts are widely used to replace or repair damaged or diseased vessels of the body. Textile vascular grafts may be implanted in the vascular system for the repair of arteries and veins. Traditionally, graft implantation is conducted in a surgical procedure requiring the body to be opened adjacent to the implantation site. Improvements in medical procedures now additionally permit graft implantation to be done in a less invasive manner. Vascular endoscopic surgery permits certain grafts to be implanted with a hollow catheter delivery system. The catheter enters the vessel either percutaneously or through a small incision. The catheter delivery system passes the graft through the lumen of the blood vessel for deployment at the desired location. In order to minimize trauma at the site of insertion of the catheter, it is desirable to employ the smallest diameter catheter possible. Accordingly, a graft which is to be implanted by the catheter delivery system would also have to be as thin as possible so that it can be radially compressed and packed inside the lumen of a hollow catheter for deployment in the blood vessel. As the size of the graft dictates the size of the catheter employed, providing a thin graft allows use of a small diameter catheter and therefore results in less trauma during implantation.
Traditional grafts currently available, having a wall thickness of 0.25 to 0.75 mm, are designed for surgical implantation and would not lend themselves to successful catheter delivery. Also, since catheter delivery is typically done under a fluoroscope or other similar x-ray type viewing mechanism, the movement of traditional textile vascular grafts during deployment cannot be fluoroscopically viewed. Further, as with traditional surgically implanted grafts, catheter implanted grafts must be longitudinally flexible to conform to the shape of the vessel which it is repairing. Also, such grafts should be capable of a certain degree of longitudinal expansion to conform to the length of the blood vessel which is to be replaced. Finally, the graft, once implanted by the catheter delivery system, must readily return to its open tubular shape and maintain that shape during use. This is particularly important where the graft is implanted by a catheter as the graft must be tightly compressed and packed so as to fit within the hollow lumen of the catheter.
In order to maintain the desired flexibility, longitudinal expansion and a certain degree of radial structural integrity, it is known to provide pleated, wave-like corrugations or crimps along the length of a textile vascular graft. These crimps provide flexibility to the graft and the ability for the graft to longitudinally expand in a spring-like manner.
An example of a traditional surgically implanted graft having wave-like crimps or corrugations to provide flexibility, stretch and radially support is shown in U.S. Pat. No. 3,142,067. As can be seen in the '067 patent, these wave-like crimps or corrugations have a relatively large amplitude so as to impart the desired degree of flexibility, stretch and structural integrity to the graft. Such large crimps in the wall of the graft presents an irregular profile of the graft wall with a relatively large difference between the major and minor diameter thereof. This area is susceptible to thrombus and plaque formation and build-up which is undesirable in a vascular graft.
It is therefore desirable to provide an improved thinly woven textile graft which exhibits sufficient spring-like elasticity and flexibility and which may be compressed in a manner which permits catheter implantation into a blood vessel.